Polishing apparatus, polishing auxiliary apparatus and polishing method

ABSTRACT

A polishing apparatus, a polishing method and a polishing auxiliary apparatus which are able to suppress clogging of the rotating grindstone and polish the work while suppressing the damage thereof are provided. A polishing apparatus  1  according to the present invention includes: a rotating shaft section  5;  a rotating table  6  which is arranged on the rotating shaft section  5  and holds a work  30  on an upper surface of the rotating table; a rotating grindstone  3  which is supported to be able to rotate in a direction opposite to the rotating direction of the rotating table  6  and to move up and down; a dress grindstone arranging section  10  arranged around the rotating shaft section  5;  and a dress grindstone  11  which is fixed onto the dress grindstone arranging section  10  with a polishing surface thereof facing a polishing surface of the rotating grindstone  3,  wherein the work is polished by bringing a surface of the rotating grindstone  3  into contact with a surface of the work  30  while rotating the rotating table  6  and the rotating grindstone  3  in directions opposite to each other, and the rotating grindstone  3  is dressed by bringing a polishing surface of the rotating grindstone  3  into contact with the polishing surface of the dress grindstone  11.

TECHNICAL FIELD

The present invention relates to a polishing apparatus, a polishing auxiliary apparatus and a polishing method.

This application claims the benefit of Japanese Patent Application No. 2008-102873 filed in the Japanese Patent Office on Apr. 10, 2008, the entire contents of which are incorporated herein by reference.

BACKGROUND ART

There is known a polishing method in which a rotating grindstone rotating relative to a work is pressed against a surface of the work to polish the work to a desired thickness. One example of the polishing apparatus of the related art for use in this polishing method is shown in FIG. 4.

The polishing apparatus 101 includes a work holding section 102 and a rotating grindstone 103 which polishes a work 200.

The work holding section 102 includes a cylindrical rotating shaft section 104 and a rotating table 105 which is rotatably supported on the rotating shaft section 104.

The rotating table 105 has an upper surface serving as a work holding surface 106 to hold the work 200 and is driven to rotate in a direction of an arrow a in the figure by a rotation driving mechanism (not shown). As the rotating table 105 is driven to rotate, the work 200 held on the work holding surface 106 revolves about the rotation axis of the rotating table 105.

The rotating grindstone 103 includes a grindstone holder 107 which is rotatably supported and a grindstone 108 which is held by the grindstone holder 107, and is arranged so that a surface of the grindstone 108 faces the work holding surface 106.

In addition, the rotating grindstone 103 is driven to rotate in a direction (arrow b direction in the figure) opposite to the rotation direction of the rotating table 105 by a rotation driving mechanism (not shown) and is operated to move between a position (an initial position) away from the work holding surface 106 and a position (a polishing position) in which the grindstone 108 contacts a surface of the work 200 by a lift operating mechanism.

In this polishing apparatus 101, if the rotating grindstone 103 is operated to move downwards while the rotating table 105 and the rotating grindstone 103 are driven to rotate in directions opposite to each other, and then the surface of the grindstone 108 is brought to be pressed against the surface of the work 200, the surface of the work 200 is slid by the grindstone 108 so that the surface of the work 200 is polished.

In addition, as a polishing apparatus of this type, there is known a polishing apparatus including a polishing tool or a tool rotation driving section for driving the polishing tool to rotate, a work holding section for holding a work which rotates parallel to a rotation axis of the tool rotation driving section, an axial driving section for moving the tool rotation driving section and the work holding section toward or away from each other in directions of their rotation axes, and a control section, the work being pressed against the tool to be flat finished, wherein a rotation axis of the tool rotation driving section or the work holding section is located on the plane of a driving reference plane which guides the driving of the axial driving section (refer to Patent Citation 1).

Furthermore, as other polishing apparatuses of this type, there is known a grinding apparatus in which a rotating table is provided to be able to rotate horizontally and a rotating grindstone is provided to be supported by a supporting column to be able to move up and down (refer to Patent Citation 2), or a surface grinding apparatus including a grinding wheel of cup wheel type with a vacuum adsorption mechanism (refer to Patent Citation 3).

Patent Citation 1: JP-A-2007-210074

Patent Citation 2: JP-A-10-058320

Patent Citation 3: JP-A-05-077147.

DISCLOSURE OF INVENTION

However, in the polishing apparatus 101 as described above, there is a problem that the polishing waste material scraped away from the work 200 causes clogging of the grindstone 108, thereby lowering a polishing performance of the grindstone 108 and causing damage to the work 200. In particular, in a case in which the work is a sapphire substrate or a SiC substrate, the polishing waste material thereof has a viscous property, thereby clogging of the rotating grindstone can easily occur.

Accordingly, in this polishing apparatus 101, in order to suppress the clogging of the grindstone 108, such measures as making the number of rotations of the rotating grindstone 103 smaller or stopping the polishing on the way to perform a dressing step more than once in which the polishing waste material attached to the rotating grindstone is removed are adopted. Here, the dressing step is performed by sliding a dress grindstone to a surface of the rotating grindstone.

However, if the number of rotations of the rotating grindstone 103 becomes small, the polishing velocity of the work decreases, which requires a long time to polish the work to a desired thickness. Additionally, if a polishing is stopped on the way to perform the dressing step, the dressing step itself also requires time in addition to the time required to polish the work. For these reasons, in the polishing apparatus 101 of the related art, it is the case that sufficient processing efficiency is not obtained, which causes the productivity decline of the processed product.

In addition, this situation is similar in the polishing apparatuses disclosed in the patent citations 1 to 3 and thus, there is a demand for a polishing apparatus which can solve the problem of the grindstone clogging and increase the polishing performance.

An advantage of some aspects of the present invention is to provide a polishing apparatus, a polishing method and a polishing auxiliary apparatus which can polish the work with good efficiency while suppressing the clogging of the rotating grindstone and can polish the work while suppressing the damage thereof.

As a result of earnest attempts to solve the above described problems, the present inventor found that the above problems are easily solved by providing the following polishing apparatus, polishing auxiliary apparatus and polishing method.

<1> A polishing apparatus according to the present invention including a rotating shaft section, a rotating table which is arranged on the rotating shaft section and holds a work on an upper surface of the rotating table, a rotating grindstone which faces the upper surface of the rotating table and is supported to be able to rotate in a direction opposite to the rotating direction of the rotating table and operated to move up and down, a dress grindstone arranging section arranged around the rotating shaft section, and a dress grindstone which is fixed onto the dress grindstone arranging section with a polishing surface thereof facing a polishing surface of the rotating grindstone, wherein the polishing waste material attached to the rotating grindstone is removed by bringing the polishing surface of the rotating grindstone into contact with the polishing surface of the dress grindstone, when the work is polished by bringing the polishing surface of the rotating grindstone into contact with a surface of the work while rotating the rotating table and the dress grindstone, and the rotating grindstone in directions opposite to each other.

<2> The polishing apparatus described in the item <1>, wherein the dress grindstone may be a ring-shaped dress grindstone which is arranged onto the dress grindstone arranging section.

<3> The polishing apparatus described in the item <1>, wherein the dress grindstone may be made up of a plurality of dress grindstone pieces which are annularly arranged side by side at a predetermined distance onto the dress grindstone arranging section.

<4> The polishing apparatus described in any one of the items <1>to <3>, wherein the dress grindstone arranging section may include a dress grindstone table which holds the dress grindstone and a dress grindstone table supporting section which supports the dress grindstone table so as to be able to move up and down.

<5> The polishing apparatus described in any one of the items <1>to <4>, wherein the dress grindstone table supporting section may include a spring which elastically supports the dress grindstone table.

<6> A polishing auxiliary apparatus according to the present invention including an annular dress grindstone arranging section and a dress grindstone fixed onto the dress grindstone arranging section, wherein the annular dress grindstone arranging section is adapted to be able to be attached to a peripheral surface of the rotating shaft section of the polishing apparatus.

<7> The polishing auxiliary apparatus described in the item <6>, wherein the dress grindstone may be made up of a ring-shaped dress grindstone piece which is arranged onto the dress grindstone arranging section.

<8> The polishing auxiliary apparatus described in the item <6>, wherein the dress grindstone may be made up of a plurality of dress grindstone pieces which are annularly arranged side by side at a predetermined distance onto the dress grindstone arranging section. <9> The polishing auxiliary apparatus described in any one of the items <6> to <8>, wherein the dress grindstone arranging section may include a dress grindstone table which holds the dress grindstone and a dress grindstone table supporting section which supports the dress grindstone table so as to be able to move up and down.

<10> The polishing auxiliary apparatus described in any one of the items <6> to <9>, wherein the dress grindstone table supporting section may include a spring which elastically supports the dress grindstone table.

<11> A polishing method according to the present invention, wherein a work is polished while polishing waste material attached to a rotating grindstone is removed by placing dress grindstones around a rotating table and bringing a polishing surface of the rotating grindstone into contact with a polishing surface of the dress grindstone, when polishing a work by bringing a polishing surface of the rotating grindstone into contact with a surface of the work while rotating the rotating table which holds the work and the grindstone in directions opposite to each other.

According to the present invention, at the time of polishing the work to a desired thickness by pressing the rotating grindstone rotating relative to the work against the surface of the work, it is possible to suppress clogging of the rotating grindstone and thus polish the work with good efficiency while suppressing damage thereof.

In addition, since the dress grindstone arranging section includes the dress grindstone table which holds the dress grindstone and the dress grindstone table supporting section which supports the dress grindstone table to be able to move up and down, even in a case in which the height of the grindstone and/or the dress grindstone is not uniform, the dress grindstone table moves to cancel out the difference in height so as to come into contact with the grindstone and remove the polishing waste material, whereby clogging of the grindstone by the dress grindstone can be uniformly prevented.

In addition, since the dress grindstone table supporting section includes a spring, even if the dress grindstone table inclines to one side, it is able to return to its original position rapidly. Therefore, it is possible to bring the grindstone and the dress grindstone into contact with each other in a good contact state at all times and to dress the grindstone during the polishing with good efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic perspective view of a whole apparatus of a polishing apparatus including a polishing auxiliary apparatus according to the present invention.

FIG. 1B is a perspective view showing another embodiment of the dress grindstone provided in the polishing apparatus including the polishing auxiliary apparatus according to the present invention.

FIG. 2 is a schematic view of the polishing apparatus shown in FIG. 1A.

FIG. 3 is a perspective view of a rotating grindstone included in the polishing apparatus shown in FIG. 1A, seen from below in FIG. 1A.

FIG. 4 is a schematic view showing a polishing apparatus of the related art.

EXPLANATION OF REFERENCE

1 . . . polishing apparatus, 2 . . . work holding section, 3 . . . rotating grindstone, 4 . . . polishing auxiliary means (polishing auxiliary apparatus), 5 . . . rotating shaft section, 6 . . . rotating table, 8 . . . grindstone holder, 9 . . . grindstone, 10 . . . dress grindstone arranging section, 11 . . . dress grindstone, 11A . . . dress grindstone piece, 11B . . . dress grindstone, 12 . . . dress grindstone table, 13 . . . dress grindstone table supporting section, 15 . . . annular section, 16 . . . supporting section, 17 . . . cushion mechanism, 18 . . . second bolt hole, 19 . . . first bolt hole, 20 . . . bolt attachment plate, 21 . . . first bolt, 24 . . . attachment plate, 25 . . . second bolt, 26 . . . spring, 30 . . . work.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a polishing apparatus, a polishing auxiliary apparatus and a polishing method according to the present invention will be described.

(Polishing Apparatus and Polishing Auxiliary Apparatus)

First, a polishing apparatus and a polishing auxiliary apparatus according to the present invention will be described.

FIGS. 1A and 1B are perspective views showing embodiments of a polishing apparatus including a polishing auxiliary apparatus according to the present invention (a polishing apparatus according to the present invention), FIG. 2 being a schematic view of the polishing apparatus shown in FIG. 1A, FIG. 3 being a perspective view of a rotating grindstone included in the polishing apparatus shown in FIG. 1A seen from below in FIG. 1A.

A polishing apparatus 1 shown in FIGS 1A and 2 includes a work holding section 2, a rotating grindstone 3 for polishing a work 30, and a polishing auxiliary means 4 for dressing a rotating grindstone 3 (a polishing auxiliary apparatus).

The work holding section 2 includes a rotating shaft section 5, a rotating table 6 and a rotation driving mechanism for driving the rotating table 6 to rotate.

The rotating table 6 has a disc shape and is fixed onto top of the rotating shaft section 5. A top surface of the rotating table 6 constitutes a work holding surface 7 for holding the work 30. The work holding surface 7 holds one sheet or plural sheets of work 30 by a fixing method such as bonding or adsorption.

Examples of materials for the rotating table 6 include, but are not limited to, ceramics such as an alumina.

The rotation driving mechanism for driving the rotating table 6 to rotate is made up of a motor (not shown in the figure), a rotating shaft section 5 which is connected to a center portion of the rotating table 6 and a rotation transfer means for transferring the rotation of the motor shaft or the like. In the rotation driving mechanism configured as above, if the motor is driven, rotation of the motor shaft is transferred to the rotating shaft section 5 via the rotation transfer means and, depending on the number of rotations of the motor, the rotation table 6 fixed to the rotating shaft section 5 is operated to rotate in a direction of arrow A in the figure. Accordingly, the work 30 held on the work holding surface 7 revolves about a rotation axis.

A rotating grindstone 3 according to this embodiment includes a grindstone holder 8, a plurality of grindstones 9 held by the grindstone holder 8 and a rotation driving mechanism for driving the grindstone holder 8 to rotate in a direction (arrow B direction in the figure) opposite to the rotation direction of the rotating table 6.

The grindstone holder 8 has a disc shape and is rotatably supported so that one side main surface thereof faces the work holding surface 7 of the rotating table 6. A rotating shaft 28 of the grindstone holder 8 is substantially parallel to a rotation axis 6 a of the rotating table 6. In this embodiment, the rotating shaft 28 of the grindstone holder 8 is set to cross over an inner circumference of the dress grindstone 11 which will be described later. This allows the grindstone 9 held by the grindstone holder 8 to be dressed with good efficiency by the dress grindstone 11 to remove the polishing waste material.

In the configuration according to this embodiment, as shown in FIG. 3, a plurality of (for example, eighteen in FIG. 3) grindstones 9 are fixed at equal distances on an outer circumference edge section of one side main surface of the grindstone holder 8. Each of the grindstones 9 has a quadrangular prism shape and is arranged side by side so that a long axis direction thereof is substantially parallel to a tangential direction of the outer circumference of the disc-shaped grindstone holder 8.

The rotation driving mechanism for driving the grindstone holder 8 to rotate includes a motor (not shown in the figure), a rotating shaft 28 fixed to the grindstone holder 8 and a rotation transfer means for transferring the rotation of the motor shaft to the rotating shaft 28 or the like, and is configured to operate the grindstone holder 8 to rotate in a direction (arrow B direction in the figure) opposite to the rotation direction of the rotating table 6. In the rotation driving mechanism configured as above, if the motor is driven, rotation of the motor shaft is transferred to the rotating shaft 28 via the rotation transfer means and, depending on the number of rotations of the motor, the grindstone holder 8 fixed to the rotating shaft 28 is operated to rotate in a direction of arrow B in the figure. Accordingly, a plurality of the grindstones 9 fixed to the grindstone holder 8 revolves about a rotation shaft 28.

In addition, the polishing apparatus 1 of this type includes a lift operating mechanism (not shown) which moves the rotating grindstone 3 up and down in an extending direction of the rotating shaft 28 (a vertical direction in an example shown in FIG. 1A). As shown in FIG. 2, the rotating grindstone 3 is operated to move between a position away from the surface of the work 30 (an initial position) and a position in which the grindstone 9 contacts a surface of the work 30 (a polishing position) by the lift operating mechanism.

In the rotation grindstone 3 configured as above, if the grindstone holder 8 is operated to move downwards while it is driven to rotate in a direction opposite to the rotation direction of the rotating table and then the surface of the grindstone 9 is pressed against the surface of the work 30, the grindstone 9 slides on the surface of the work 30, whereby the surface of the work 30 is polished. This makes the work 30 be processed so that a top surface thereof becomes a smooth surface having a surface roughness of a desired range.

In addition, as shown in FIGS. 1A and 2, the polishing apparatus 1 according to the present invention is characterized in that a polishing auxiliary means (polishing auxiliary apparatus) 4 is arranged around the rotating table 6.

The polishing auxiliary means (polishing auxiliary apparatus) 4 is roughly made up of a dress grindstone arranging section 10 and a plurality of dress grindstones 11 which are arranged on the dress grindstone arranging section 10.

The dress grindstone arranging section 10 includes a dress grindstone table 12 and a dress grindstone table supporting section 13 which supports the dress grindstone table 12.

The dress grindstone table 12 has an annular shape of dimensions in which an inner circumference thereof is slightly larger than an outer circumference of the rotating shaft section 5, and is arranged around an upper portion of the rotating shaft section 5. The dress grindstone table 12 is supported by the dress grindstone table supporting section 13 to be able to move up and down within a predetermined height range. Also, on an outer circumferential edge section of the dress grindstone table 12, a plurality of bolt holes 14 through which second bolts 25 which will be described later are inserted are intermittently provided along the circumference.

In addition, the dress grindstone table 12 is cut out at a portion corresponding to a first bolt attachment plate 20 which will be described later. Accordingly, it is possible to easily put a tool on a head section of the first bolt 21 and to perform an operation to fasten a first bolt 21.

On the dress grindstone table 12, a dress grindstone 11 made up of a plurality of (sixteen in FIG. 1A) dress grindstone pieces 11A which are annularly arranged is fixed.

Each of the dress grindstone pieces 11A has a brick shape and is annularly arranged side by side on an outer circumferential section of the dress grindstone table 12 so that a long axis direction thereof is substantially parallel to a tangential direction of the outer circumference of the dress grindstone table 12. In addition, each of the dress grindstones 11 is dimensioned such that its surface is substantially flush with a surface of the work 30.

With these configurations, the dress grindstone rotates integrally with a rotating table. If the grindstone holder 8 is operated to move downwards while being driven to rotate in a direction opposite to the rotation direction of the rotating table and then the surface of the grindstone 9 is pressed against the surface of the work 30, the surface of the grindstone 9 is also pressed against the surface of the dress grindstone 11.

Accordingly, while the grindstone 9 slides on the surface of the work 30, the surface thereof is slid by the dress grindstone 11. Thus, simultaneously with the polishing of the work 30, a dressing of the grindstone 9 by the dress grindstone 11 is performed, so that the polishing waste material can be removed. Moreover, the dress grindstone piece 11A having a brick shape used in this embodiment is one example, but one dress grindstone 11B which is preliminarily formed as a ring shape as shown in FIG. 1B may be arranged on an outer circumferential section of the dress grindstone table 12.

For this reason, at the time of polishing the work 30, clogging of the grindstone 9 by the polishing waste material of work 30 is suppressed, so that the grindstone 9 is able to exhibit a favorable polishing performance over the entire polishing. In addition, it is possible to suppress generation of damage to the work 30 by the polishing waste material.

In addition, if a dressing of the grindstone 9 is performed simultaneously with a polishing of the work 30, it is possible to shorten a time required to complete a polishing (to polish the work to a desired thickness) in comparison with a case in which a dressing is performed after a polishing is stopped.

Due to these reasons, in the polishing apparatus 1 according to this embodiment, it is possible to obtain high processing efficiency in a polishing and to remarkably increase the productivity of the polished product.

The dress grindstone table supporting section 13 is made up of an annular section 15 for supporting the dress grindstone table 12, a supporting section 16 for supporting the annular section 15 and a cushion mechanism 17.

The annular section 15 has an annular shape of dimensions in which an inner circumference thereof is slightly larger than an outer circumference of the rotating shaft section, and is arranged around the rotating shaft section 5 so as to contact a lower surface of the dress grindstone table 12. Also, on an outer circumferential edge section of the annular section 15, first bolt holes 19 through which first bolts 21 which will be described later are inserted and second bolt holes 18 through which bolts 25 and springs 26 which will be described later are inserted are respectively provided in necessary numbers along the circumference. Into the first bolt holes 19 among these holes, the first bolts 21 are screwed. Also, into the second bolt holes 18, the bolts 25 and the springs 26 are inserted.

The supporting section 16 is made up of a first bolt attachment plate 20, a first bolt 21 and an auxiliary bolt 23.

Under a portion to which the bolt 25 and the spring 26 described above are arranged, attachment plates 24 are provided, each of which is located below the annular section 15 and intermittently along the circumference of the rotating shaft section 5 and is fixed in a suspended manner to an outer circumference of the rotating shaft section 5 by an auxiliary bolt 27.

In addition, in the supporting section 16, an outer circumferential section of the rotating shaft section 5 is provided with the bolt attachment plate 20, and the first bolt 21 screwed into the bolt hole 19 of the annular section 15 above that section and the auxiliary bolt 23 are screwed into or in contact with the attachment plate 20.

The plurality of second bolts 25 are, with their heads directing upwards, respectively inserted into a bolt hole 14 of the dress grindstone table 12, the second bolt hole 18 of the annular section 15 and a bolt hole of the second bolt attachment plate 24. Also, a lower end of each of the second bolts 25 is screwed into a nut so that the nut contacts a lower surface of the second bolt attachment plate 24. This prevents each of the second bolts 25 from escaping out of each of the bolt holes, respectively.

Each of the second bolts 25 is enclosed in a spring 26. Each of the springs 26 is arranged between an upper surface of the second bolt attachment plate 24 and a lower surface of the dress grindstone table 12. Accordingly, the spring 26 serves to elastically support the dress grindstone table 12.

In the dress grindstone table supporting section 12 configured as above, in an initial state, the annular section 15 is elastically supported by the spring 26. A height position of the dress grindstone table 12 in the initial state is called “an initial position”.

The initial position may be arbitrarily set depending on a thickness of the work, a polished amount of the work and a kind of the spring 26. Although it is not particularly limited, in the case of an arrangement such as FIG. 1A, it is preferable to set a use surface of the dress grindstone 11 slightly higher than a polishing surface of the work put on the rotating table 6. Also, although it may be possible to reset the initial position during a polishing in accordance with a polishing amount on the way, it is preferable to make the initial position constant from the viewpoint of productivity.

In this state, if external force is applied to a part of the dress grindstone table 12, the dress grindstone table 12 can be inclined to a necessary direction since it is elastically supported by the spring 26.

As the dress grindstone table 12 exhibits such behavior, when each of the grindstones 9 contacts the dress grindstones 11 while revolving, each of the grindstones 9 and each of the dress grindstones 11 contacts each other uniformly even in a case in which each of the grindstones 9 and/or each of the dress grindstones 11 has a non-uniform height, since the dress grindstone table 12 sinks down at a part where the height is high. Also, since the dress grindstone 12 is adapted to return its original state rapidly even if it inclines to one side thereof, it is possible to bring the grindstones 9 and each of the dress grindstones 11 into contact with each other in a good contact state at all times and to dress each of the grindstones 9 with good efficiency.

Incidentally, although a state in which the polishing auxiliary means (polishing auxiliary apparatus) 4 is already attached to the rotating shaft section 5 is described in the polishing apparatus 1 according to this embodiment, since the polishing auxiliary means 4 is roughly made up of a dress grindstone arranging section 10 and a plurality of dress grindstones 11 which are arranged on the dress grindstone arranging section 10, the polishing auxiliary means 4 may be attached to a disc-shaped rotating shaft section which is different from the rotating shaft section 5 shown in FIGS. 1A and 2.

Since the dress grindstone arranging section 10 includes a dress grindstone table 12 and a dress grindstone table supporting section 13 which supports the dress grindstone table 12, it is possible to attach a separate polishing auxiliary means 4 to a disc-shaped rotating shaft section of the polishing apparatus of the related art by mounting and fixing a polishing auxiliary means 4 to a general disc-shaped rotating shaft section not having the polishing auxiliary means 4 attached thereto.

By configuring the polishing auxiliary means 4 as being attached to a separate rotating shaft section, it is possible to apply the polishing auxiliary means 4 having a configuration according to the present invention to a polishing apparatus of the related art having a disc-shaped rotating shaft section which is already used in production sites.

Accordingly, it is possible to modify a polishing apparatus of the related art into a novel polishing apparatus which exhibits an acting effect of the present invention and to increase production efficiency by making good use of the ready-made apparatuses in use without discarding them.

(Polishing Method)

Next, a polishing method according to the present invention will be described with reference to a case of using a polishing apparatus shown in FIGS. 1A and 2.

As shown in FIGS. 1A and 2, firstly, the polishing apparatus 1 is in a position in which the rotating grindstone 3 is spaced from a surface of the work 30 (an initial position).

Next, a work (a substrate to be processed) 30 is mounted onto a work holding surface 7 of the rotating table 6.

Examples of the work 30 include, but are not limited to, metal materials such as iron, steel, copper, semiconductor materials such as sapphire, silicon, SiC or a substrate composed of ceramics or the like. According to the present invention, even in a case of sapphire or SiC in which clogging easily occurs, it is possible to suppress clogging of the rotating grindstone and perform a polishing with good efficiency.

The number of works to be attached to the work holding surface 7 may be singular or plural and is appropriately set depending on a diameter of the work holding surface 7 or a diameter of the work 30. For example, in a case in which a diameter of the work holding surface 7 is about 300 mm and the work 30 is a 4-inch substrate, it is possible to mount about three sheets of a substrate on the work holding surface 7.

A rotation driving mechanism including a rotating shaft section 5 drives the rotating table 6 to rotate with a predetermined number of rotations in a direction of arrow A in the figure. This makes the work 30 held by the work holding surface 7 revolve about the rotating axis horizontally.

In addition, the rotation driving mechanism included in the rotating grindstone 3 drives the grindstone holder 8 to rotate with a predetermined number of rotations in a direction of arrow B in the figure. This makes a plurality of grindstones 9 fixed to the grindstone holder 8 revolve horizontally about the rotating axis.

Next, by means of the lift operating mechanism, the rotating grindstone 3 is moved down from an initial position to a position in which a surface of the grindstone 9 contacts a surface of the work 30 (a polishing position). This presses the surface of the grindstone 9 against the surface of the work 30.

If the surface of the revolving work comes into contact with the surface of the grindstone 9 which revolves in a direction opposite to the revolving direction of the work, the grindstone 9 slides on the surface of the work 30 and thereby polishes the surface of the work 30. This processes the work to have a thin thickness and the surface thereof is polished to a flat surface having a desired roughness.

In addition, at this time, the surface of the grindstone 9 is pressed against the surface of the dress grindstone 11. Accordingly, the surface of the grindstone 9 is ground by the dress grindstone 11 while the grindstone 9 polishes the surface of the work 30, so that a dressing of the grindstone 9 by the dress grindstone 11 is performed simultaneously with a polishing of the work 30. As a result, it is possible to suppress the phenomenon that clogging is caused on the surface of the grindstone 9 by the polishing waste material of the work or the like and to support a polishing which is faster than the apparatus of the related art.

Then, if each work 30 is polished to a desired thickness, the lift operating mechanism moves up the rotating grindstone 3 to a position away from the surface of the work 30 (an initial position), so that the work 30 can be removed.

As described above, in the polishing method according to the present invention, it is possible to perform a dressing of the grindstone 9 simultaneously with a polishing of the work 30.

For this reason, at the time of polishing the work 30, clogging of the grindstone 9 by the polishing waste material of the work 30 is suppressed, so that the grindstone 9 can exhibit an excellent polishing performance over the entire polishing.

In addition, if a polishing of the work 30 and a dressing are simultaneously performed, it is possible to shorten the time required to complete a polishing (to polish the work to a desired thickness) in comparison with a case in which a dressing is performed after a polishing is stopped.

Due to these reasons, in this polishing method, it is possible to obtain high processing efficiency and to remarkably increase the productivity of the processed product.

For example, if the polishing apparatus shown in FIGS. 1A and 2 is used to polish a sapphire substrate (thickness: 700 μm, diameter: 4 inches) to a thickness of 80 μm, the polishing may be performed at a polishing velocity of 50 to 100 μm/min, whereas if the polishing apparatus of the related art (the polishing apparatus shown in FIG. 4) is used to perform the same polishing, the polishing may be performed only at a polishing velocity of 10 μm/min. That is, by using the polishing apparatus (polishing method) according to the present invention, it is possible to obtain a polishing velocity 5 to 10 times faster than the related art.

Furthermore, each section constituting the polishing apparatus and the polishing auxiliary apparatus and each step of the polishing method in the above described embodiment is just one example and can be changed without departing from the scope of the invention.

INDUSTRIAL APPLICABILITY

The polishing apparatus, the polishing auxiliary apparatus and the polishing method according to the present invention enable the performance of a polishing with good efficiency without damaging a work by suppressing the clogging of the rotating grindstone, thus having suitable characteristics for polishing a sapphire substrate or a SiC substrate which is liable to cause clogging of the rotating grindstone. 

1. A polishing apparatus, comprising: a rotating shaft section, a rotating table which is arranged on the rotating shaft section and which holds a work on an upper surface of the rotating table, a rotating grindstone which faces the upper surface of the rotating table and which is supported to be able to rotate in a direction opposite to the rotating direction of the rotating table and operated to move up and down, a dress grindstone arranging section arranged around the rotating shaft section, and a dress grindstone which is fixed onto the dress grindstone arranging section with a polishing surface thereof facing a polishing surface of the rotating grindstone, wherein polishing waste material attached to the rotating grindstone is removed by bringing the polishing surface of the rotating grindstone into contact with the polishing surface of the dress grindstone, when the work is polished by bringing the polishing surface of the rotating grindstone into contact with a surface of the work while rotating the rotating table and the dress grindstone, and the rotating grindstone in directions opposite to each other.
 2. The polishing apparatus according to claim 1, wherein the dress grindstone is a ring-shaped dress grindstone which is arranged onto the dress grindstone arranging section.
 3. The polishing apparatus according to claim 1, wherein the dress grindstone is made up of a plurality of dress grindstone pieces which are annularly arranged side by side at a predetermined distance onto the dress grindstone arranging section.
 4. The polishing apparatus according to claim 1, wherein the dress grindstone arranging section includes a dress grindstone table which holds the dress grindstone and a dress grindstone table supporting section which supports the dress grindstone table so as to be able to move up and down.
 5. The polishing apparatus according to claim 4, wherein the dress grindstone table supporting section includes a spring which elastically supports the dress grindstone table.
 6. A polishing auxiliary apparatus, comprising: an annular dress grindstone arranging section and a dress grindstone fixed onto the dress grindstone arranging section, wherein the dress grindstone arranging section is configured to be able to be attached to a peripheral surface of the rotating shaft section of a polishing apparatus.
 7. The polishing auxiliary apparatus according to claim 6, wherein the dress grindstone is made up of a ring-shaped dress grindstone which is arranged onto the dress grindstone arranging section.
 8. The polishing auxiliary apparatus according to claim 6, wherein the dress grindstone is made up of a plurality of dress grindstone pieces which are annularly arranged side by side at a predetermined distance onto the dress grindstone arranging section.
 9. The polishing auxiliary apparatus according to claim 6, wherein the dress grindstone arranging section includes a dress grindstone table which holds the dress grindstone and a dress grindstone table supporting section which supports the dress grindstone table so as to be able to move up and down.
 10. The polishing auxiliary apparatus according to claim 9, wherein the dress grindstone table supporting section includes a spring which elastically supports the dress grindstone table.
 11. A polishing method, wherein a work is polished while polishing waste material attached to a rotating grindstone is removed by placing dress grindstones around a rotating table and bringing a polishing surface of the rotating grindstone into contact with a polishing surface of the dress grindstone, when polishing a work by bringing a polishing surface of the rotating grindstone into contact with a surface of the work while rotating the rotating table which holds the work and the grindstone in directions opposite to each other. 